This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The project is about studying the structural and dynamic properties of large protein machinaries. More specifically, we will study the SecA motor ATPase (204 kDa) and the SecB chaperone (70 kDa), two vital components of the general secretion (Sec) pathway. We are interested in understanding how the two proteins interact with each other and with other ligands during the secretion proc